阅读说明：本技术 用于热障涂层(tbc)面涂层的高熵氧化物 (High entropy oxide for Thermal Barrier Coating (TBC) topcoats ) 是由 J·何 H·L·洛夫洛克 N·周 T·哈灵顿 T·沙罗贝姆 于 2019-10-09 设计创作，主要内容包括：热障涂层(TBC)面涂层,其为具有高位形熵的高熵氧化物(HEO),包含至少五种不同的氧化物形成性金属阳离子,在直至和超过优选至少2300°F的面涂层工作温度的预料不到的宽温度范围内为单相或单晶结构,诸如四方或立方型。TBC面涂层表现出低导热率、良好的耐烧结性、优异的相稳定性和良好的热循环性能。至少五种不同的氧化物形成性金属阳离子包括：a)过渡金属：Sc、Y、Ti、Zr、V、Nb、Ta、Cr、Mo、W、Mn、Re、Fe、Ru、Co、Ni、Cu或Zn中的至少一种,和/或镧系元素La、Ce、Pr、Nd、Pm、Sm、Eu、Gd、Tb、Dy、Ho、Er、Yb或Lu中的至少一种。所述至少五种不同的氧化物形成性金属阳离子中的一种也可以包含碱土金属：Be、Mg、Ca、Sr或Ba中的至少一种。(A Thermal Barrier Coating (TBC) topcoat which is a High Entropy Oxide (HEO) having high azimuthal entropy, comprising at least five different oxide forming metal cations, is of single phase or single crystal structure, such as tetragonal or cubic, over an unexpectedly wide temperature range up to and beyond the topcoat operating temperature, preferably at least 2300 ° F. TBC topcoats exhibit low thermal conductivity, good sintering resistance, excellent phase stability, and good thermal cycling performance. The at least five different oxide-forming metal cations include: a) transition metal: at least one of Sc, Y, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Co, Ni, Cu or Zn, and/or at least one of the lanthanides La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb or Lu. One of the at least five different oxide-forming metal cations may also comprise an alkaline earth metal: be. At least one of Mg, Ca, Sr, or Ba.)

1. A thermal barrier coating, comprising:

a topcoat, wherein the topcoat is ofA High Entropy Oxide (HEO) with high formal entropy, said HEO being M_xO_yWherein M represents at least five different oxide-forming metal cation groups, x represents the number of metal cations (M) or atoms, and y represents the number of oxyanions (O) or atoms,

wherein said HEO maintains phase composition without transformation from room temperature to topcoat service temperature range, and

the at least five different oxide-forming metal cations (M) include:

a) at least one transition metal selected from Sc, Y, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Co, Ni, Cu or Zn, and/or

b) At least one of lanthanide La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb or Lu.

2. The thermal barrier coating of claim 1, wherein one of the at least five different oxide-forming metal cations (M) comprises at least one of an alkaline earth metal Be, Mg, Ca, Sr, or Ba.

3. The thermal barrier coating of claim 1, wherein the at least five different oxide-forming metal cations (M) comprise:

a) at least one of transition metals Y, Ti, Zr, V, Cr, Mo or W, and/or

b) At least one of lanthanide La, Ce, Pm, Sm, Eu, Gd, Tb, Dy, Er or Yb.

4. The thermal barrier coating of claim 3, wherein one of the at least five different oxide-forming metal cations (M) comprises at least one of an alkaline earth metal Mg or Ca.

5. The thermal barrier coating of claim 1, wherein the at least five different oxide-forming metal cations (M) comprise Y, Zr, Ca, Gd, La, Yb, Ti, or Ce.

6. The thermal barrier coating of claim 1, comprising at least five different metal oxides selected from the group consisting of:

a) y in an amount of 5 to 20% by weight₂O₃，

b) ZrO in an amount of 12 to 55% by weight₂，

c) CaO in an amount of 0 to 15% by weight,

d) gd in an amount of 0 to 30% by weight₂O₃，

e) La in an amount of 0 to 26% by weight₂O₃，

f) Yb in an amount of 0 to 32% by weight₂O₃，

g) TiO in an amount of 0 to 10 wt%₂Or is or

h) CeO in an amount of 0 to 18% by weight₂，

Wherein the percentages of the at least five selected metal oxides total at least 97% by weight.

7. The thermal barrier coating of claim 1, comprising at least five different metal oxides selected from the group consisting of:

a) y in an amount of 8 to 18% by weight₂O₃，

b) ZrO in an amount of 17 to 52% by weight₂，

c) CaO in an amount of 0 to 11% by weight,

d) gd in an amount of 0 to 28% by weight₂O₃，

e) La in an amount of 0 to 24% by weight₂O₃，

f) Yb in an amount of 0 to 30% by weight₂O₃，

g) TiO in an amount of 0 to 7 wt%₂Or is or

h) CeO in an amount of 0 to 15% by weight₂，

Wherein the percentages of the at least five metal oxides total at least 97% by weight.

8. The thermal barrier coating of claim 1, comprising: y in an amount of 8 to 12% by weight₂O₃ZrO in an amount of 48 to 55% by weight₂Yb in an amount of 14 to 18% by weight₂O₃TiO in an amount of 4 to 8% by weight₂And CeO in an amount of 12 to 17% by weight₂Said percentages amounting to at least 97% by weight.

9. The thermal barrier coating of claim 8, further comprising at least one additional metal oxide in an amount of up to 2 weight percent, the weight percentages totaling up to at least 99 weight percent.

10. The thermal barrier coating of claim 8, further comprising HfO in an amount of up to 2% by weight₂Said weight percentages amounting to at least 99% by weight.

11. The thermal barrier coating of claim 1, comprising:

the following three metal oxides:

y in an amount of 13 to 19% by weight₂O₃，

ZrO in an amount of 14 to 25% by weight₂And are and

gd in an amount of 20 to 30% by weight₂O₃And an

Any two of the following metal oxides:

yb in an amount of 23 to 32% by weight₂O₃，

La in an amount of 18 to 25% by weight₂O₃Or is or

CaO in an amount of 6 to 12% by weight,

the percentages of the five metal oxides add up to at least 97%.

12. The thermal barrier coating of claim 1, wherein the oxide has a shape entropy of at least 1.5R/mole, where R is the gas constant J-K^-1·mol^-1。

13. The thermal barrier coating of claim 1, wherein the five or more different oxide-forming metal cations are present in a composition of 5 to 35 atomic%.

14. The thermal barrier coating of claim 1, wherein M represents at least one member of group II of the periodic table of elements.

15. The thermal barrier coating of claim 1, wherein M represents at least two lanthanides.

16. The thermal barrier coating of claim 1, wherein M represents at least two transition metals.

17. The thermal barrier coating of claim 1, further comprising a thermal barrier coating bond coat.

18. The thermal barrier coating of claim 1, wherein the HEOF is a single phase or single crystal structure from room temperature to at least 2,000 ° F.

19. The thermal barrier coating of claim 1, wherein the HEO is a cubic single phase or single crystal structure from room temperature to at least 2,000 ° F.

20. The thermal barrier coating of claim 1, wherein the HEOF is a single phase or single crystal structure from 1800 ° F to 2600 ° F.

21. The thermal barrier coating of claim 1, wherein the HEO is a single phase or single crystal structure of a tetragonal shape from room temperature to at least 2,000 ° F.

22. The thermal barrier coating of claim 1, wherein the HEO is a single phase or single crystal structure from room temperature to a melting point of the HEO.

23. The thermal barrier coating of claim 1, wherein the HEO does not undergo a phase transition to a different crystalline structure from at least 700 ° F to a melting point of the HEO.

24. A thermal barrier coating material, comprising:

a High Entropy Oxide (HEO) having a high formal entropy, said HEO being M_xO_yWherein M represents at least five different oxide-forming metal cation groups, x represents the number of metal cations (M) or atoms, and y represents the number of oxyanions (O) or atoms,

wherein the HEO is a single phase throughout the operating temperature range of the topcoat, an

The at least five different oxide-forming metal cations (M) include:

a) at least one transition metal selected from Sc, Y, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Co, Ni, Cu or Zn, and/or

b) At least one of lanthanide La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb or Lu.

25. The thermal barrier coating of claim 24, wherein one of the at least five different oxide-forming metal cations (M) comprises at least one of an alkaline earth metal Be, Mg, Ca, Sr, or Ba.

26. The thermal barrier coating material of claim 24, wherein the at least five different oxide-forming metal cations (M) comprise Y, Zr, Ca, Gd, La, Yb, Ti, or Ce.

27. The thermal barrier coating material of claim 24, comprising at least five different metal oxides selected from the group consisting of:

a) is 5% by weightY in an amount of 20% by weight₂O₃，

b) ZrO in an amount of 12 to 55% by weight₂，

c) CaO in an amount of 0 to 15% by weight,

d) gd in an amount of 0 to 30% by weight₂O₃，

e) La in an amount of 0 to 26% by weight₂O₃，

f) Yb in an amount of 0 to 32% by weight₂O₃，

g) TiO in an amount of 0 to 10 wt%₂Or is or

h) CeO in an amount of 0 to 18% by weight₂，

Wherein the percentages of the at least five metal oxides total at least 97% by weight.

28. The thermal barrier coating material of claim 24, comprising: y in an amount of 8 to 12% by weight₂O₃ZrO in an amount of 48 to 55% by weight₂Yb in an amount of 14 to 18% by weight₂O₃TiO in an amount of 4 to 8% by weight₂And CeO in an amount of 12 to 17% by weight₂Said percentages amounting to at least 97% by weight.

29. The thermal barrier coating material of claim 24, which is at least one of a powder, a wire, a rod, an ingot, and a rod.

30. A thermal spray powder comprising the topcoat material of claim 24.

31. A coated substrate comprising a substrate and the thermal barrier coating of claim 17, wherein the topcoat of the thermal barrier coating is bonded to the substrate by the thermal barrier coating bond coat.

32. A method for reducing delamination of a topcoat from a substrate comprising bonding the thermal barrier coating of claim 17 to a substrate, wherein the topcoat of the thermal barrier coating is bonded to the substrate by the thermal barrier coating bond coat.

33. The thermal barrier coating material of claim 24, which is agglomerated and sintered.

34. The thermal barrier coating material of claim 33, in powder form.

35. A method for producing a thermal barrier coating comprising agglomerating and sintering the thermal barrier coating material of claim 24 to obtain sintered agglomerates and forming the sintered agglomerates into a powder for thermal spraying.

Technical Field

The present invention relates to topcoat materials for Thermal Barrier Coatings (TBCs) having excellent phase and dimensional stability over a wide temperature range, as well as good thermal cycling performance and low thermal conductivity. The topcoat material may be in the form of a powder, alloy, topcoat or coating layer, and may be employed with the bond coat material in the form of a thermal spray powder to obtain a Thermal Barrier Coating (TBC) system. The invention also relates to a method for reducing delamination of a topcoat from a bond coat and a substrate, such as a gas turbine engine component.

Background

The complete thermal barrier coating system includes a topcoat layer, such as a Thermal Barrier Coating (TBC), and a bond coat or bond coat layer. Common bond coats are made of MCrAlY alloys, where M represents Ni, Co, Fe, or a combination thereof. To improve the performance of the bond coat, Hf, Re and Pt and various other rare earth elements are often added to the advanced bond coat. Common topcoats are made from zirconia (ZrO) stabilized with one or more of yttria, ytterbia, ceria, titania, magnesia, calcia, lanthana, or dysprosia₂) Made of, or consisting of, gadolinium zirconate (Gd)₂Zr₂O₇) And (4) preparing.

TBC systems are applied and bonded to substrates such as superalloys and protect the substrate in hot and harsh environments, such as in gas turbine engine environments. The tie coat or tie layer is between the topcoat and the substrate and bonds the topcoat to the substrate. The tie coat or tie layer is formed from a tie coat material, which may be in powder form for application to the substrate. The bond coat or bond coat formed from the bond coat material affects the thermal cycle fatigue and sulfidation resistance of a topcoat (such as a TBC), the effectiveness of which can be evaluated by the furnace cycle life of the TBC in the presence and absence of sulfur. TBC may deteriorate due to high temperature and harsh environment (such as the presence of sulfur). For example, the use of high sulfur content oils as fuel in industrial gas turbines with TBC's is an important factor in reducing TBC life.

One significant failure of the complete TBC system occurs at the bond coat/top interface. When the TBC system is exposed to high temperatures, an oxide layer known as Thermally Grown Oxide (TGO) nucleates and grows between the bond coat and the top coat, thereby preventing further oxygen in-diffusion to prevent oxidation of the substrate. A dense a-alumina TGO layer is desirable because it effectively blocks oxygen diffusion inward and also grows slowly on its own. However, there is a significant difference in the coefficient of thermal expansion of the topcoat, bond coat and TGO. When TBC systems undergo thermal cycling (room temperature-service temperature-room temperature), significant internal stresses caused by temperature changes can build up at the topcoat/TGO interface and the TGO/bond coat interface. As the TGO layer thickens, the thermal internal stresses become higher and higher, and eventually the topcoat (such as TBC) fails due to delamination caused by the thermal internal stresses. Modern jet engines and industrial gas turbines are seeking higher operating temperatures in order to improve performance and energy efficiency, and therefore require higher thermal shock resistance of TBC systems.

It has been found that changes or phase changes in the crystal structure (e.g., from a tetragonal crystal structure to a cubic or fluorite type crystal structure or phase, or vice versa) can be accompanied by significant changes in the volume of the topcoat when subjected to changes from room temperature to higher service temperatures and vice versa, which can result in detrimental delamination of the topcoat from the bond coat or substrate.

Thermal Barrier Coatings (TBCs) are a key technology for aircraft engines and industrial gas turbines. The basic TBC system includes a (Ni, Co, Fe) CrAlY bond coat and an oxide ceramic topcoat. The topcoat is typically of 7-8 wt% Y₂O₃Y of (A) is₂O₃Stabilized ZrO₂. The key requirements of TBC are: low thermal conductivity; phase and dimensional stability over the entire operating temperature range; resistance to sintering at the high temperature end of the operating temperature range; as well as good oxidation and thermal cycling performance of the combination coating system. For aircraft engines, resistance to "CMAS" erosion is also important. The molten CMAS (calcium magnesium aluminosilicate) deposits ingested with the intake air penetrate and interact with the Thermal Barrier Coating (TBC) in the gas turbine engine, degrading the zirconia-based TBC and overall TBC performance. As gas turbine engines are driven to operate at higher temperatures to maximize efficiency, components become more susceptible to attack by Calcium Magnesium Aluminosilicate (CMAS) deposits. Molten CMAS is known to interact with TBCs both thermochemically by dissolving the ceramic and re-precipitating it as a new or altered phase, and thermomechanically by infiltrating the porosity and reducing strain tolerance.

Many variations of the Thermal Barrier Coating (TBC) topcoat chemistries described above are in use today. However, this basic TBC system is now approaching its limits, particularly in terms of thermal conductivity.

The High Entropy Oxide (HEO) has a high formal entropy S: (_{Bit shape}) An oxide of (a). They typically contain five or more different metal cation types and oxygen to form one or more oxide sub-lattices. HEO has high levels of lattice distortion and other lattice defects. This reduces the thermal conductivity and may improve mechanical properties, such as toughness. Bit shape entropy S of HEO_{Bit shape}Typically 1.5R/mole or greater, where R is the gas constant 8.314 J.K^-1mol^-1(ii) a Using S_{Bit shape}This definition of value is a generally accepted definition of high entropy material.

Numerous metal oxides are knownAnd thermal barrier coatings with lower thermal conductivity, but their use as top coats having a single phase that does not undergo a phase change over a wide temperature range is not disclosed. For example, U.S. Pat. No. 6,812,176 to Zhu et al, the disclosure of which is incorporated herein by reference in its entirety, discloses a thermal barrier coating composition that is about 46-97 mol% of a base oxide, about 2-25 mol% of a primary stabilizer, about 0.5-12.5 mol% of a group A dopant, and about 0.5-12.5 mol% of a group B dopant. The base oxide is selected from ZrO₂、HfO₂And combinations thereof. The primary stabilizer dopant is selected from Y₂O₃、Dy₂O₃And Er₂O₃And combinations thereof. The group A dopant is selected from the group consisting of alkaline earth oxides, transition metal oxides, rare earth oxides, and combinations thereof. The B group dopant is selected from Nd₂O₃、Sm₂O₃、Gd₂O₃、Eu₂O₃And combinations thereof. The Zhu patent does not disclose that the composition is a High Entropy Oxide (HEO) or S with greater than 1.5R_{Bit shape}。

U.S. Pat. Nos. 7,001,859 and 7,186,466, each to Zhu et al, the disclosures of which are each incorporated herein by reference in their entirety, disclose thermal barrier coating compositions having 46-97 mole percent of a base oxide, 2-25 mole percent of a primary stabilizer, 0.5-25 mole percent of a group A dopant, and 0.5-25 mole percent of a group B dopant. The base oxide is selected from ZrO₂、HfO₂And combinations thereof, the primary stabilizer being selected from Y₂O₃、Dy₂O₃、Er₂O₃And combinations thereof; the B group dopant is selected from Nd₂O₃、Sm₂O₃、Gd₂O₃、Eu₂O₃And combinations thereof; and the group a dopant is selected from the group consisting of rare earth oxides, alkaline earth metal oxides, transition metal oxides, and combinations thereof, but excludes those species included in the group of base oxides, group B dopants, and primary stabilizers. The ratio of the mole percent of the group a dopant to the mole percent of the group B dopant in the composition is between about 1:10 and about 10: 1. None of the Zhu patents disclose compositions that are High Entropy Oxides (HEO) or S with greater than 1.5R_{Bit shape}。

The high entropy (S.sub.D) of any composition can be calculated using standard thermodynamic formulas such as those described in the PhD.A. 2016 "Entropical-stabilized oxides: applications of novel classes of multicomponent materials" by C.M. Rost in North Carolina State university_{Bit shape}Greater than 1.5R), the disclosure of which is incorporated herein by reference in its entirety.

U.S. patent No. 7,001,859 to Dorfman et al and U.S. patent No. 9,975,812 to Dousburg et al, the disclosures of which are incorporated herein by reference in their entirety, each disclose ceramic materials for use in thermal barriers and high temperature wear resistant coatings for high temperature cycling applications. The material is composed primarily of ultrapure stabilized zirconia (ZrO) having unusually high sintering resistance₂) And/or hafnium oxide (HfO)₂) Alloying to achieve a high service life. It is disclosed that the change in the microstructure of the coating is retarded during the service life. The material has about 4 to 20% by weight of one or more rare earth oxide stabilizers; and the balance of zirconium oxide (ZrO)₂) Hafnium oxide (HfO)₂) And combinations thereof, wherein zirconium oxide (ZrO)₂) And/or hafnium oxide (HfO)₂) Is partially stabilized by the stabilizer, and wherein the total amount of impurities is less than or equal to 0.15% by weight. These patents disclose zirconia alloys having: 1) some of the highest melting points of all ceramics, and this theoretically means some of the highest temperatures at which sintering can start to occur; 2) one of the lowest thermal conductivities of all ceramics; and 3) one of the highest coefficients of thermal expansion of all ceramics, and thus is most compatible with transition metal alloys during thermal cycling. However, according to these patents, zirconia alone does not meet the coating requirements because it undergoes a tetragonal to monoclinic phase transformation during thermal cycling. It is speculated that this transformation leads to detrimental volume changes, resulting in large strain differences between the coating and the substrate. When the resulting stress exceeds the strength of the bond between the coating and the substrate, the coating will peel off. For this reason, a phase stabilizer such as yttrium oxide is added to zirconium oxide and/or hafnium oxide, which suppresses monoclinic from a tetragonal directionAnd (4) phase transition. These compositions are not disclosed as High Entropy Oxides (HEO) or S with greater than 1.5R_{Bit shape}。

U.S. patent application publication nos. 2018/0022928 and 2018/0022929, each to Blush, the disclosures of which are incorporated herein by reference in their entirety, disclose coated articles that support high entropy nitride and/or oxide thin film inclusive coatings. The high entropy alloy system is thermally stable and can be used for optical coatings. A first material system that may be used includes SiAlN with one or more (preferably two or more) of elements such as Hf, Y, Zr, Ti, Ta and Nb. A second material system that may be used includes TiO with one or more (preferably two or more) of elements such as Fe, Co, Ni, Sn, Zn and N. The material system may in some cases be a high-index material that may be used as a substitute for titanium oxide in the stack. It is disclosed that current high entropy alloys are known to have high temperature stability due to extremely high entropy contributions. This is related to their equiatomic or near-equiatomic composition as well as the high number of elemental constituents. Δ G = Δ H-T Δ S (where Δ G is the change in gibbs free energy, Δ H is the enthalpy, T is the temperature, and Δ S is the entropy) is known. The phase with the lowest gibbs free energy of formation will be the phase formed at equilibrium, so increasing entropy will increase the likelihood of phase stabilization. According to the term Blush, in general, Δ S of conventional low entropy materials_{Bit shape}About 1R (or sometimes lower), Δ S for medium entropy materials_{Bit shape}About 1R to about 1.5R, Δ S of high entropy material_{Bit shape}Greater than about 1.5. However, it is disclosed that the boundaries between low and medium and high do not have to be precisely delineated. For example, even though Δ S is normally expected_{Bit shape}May be slightly less than 1.5R, but for these purposes some materials, possibly with four constituent materials, may still be considered high entropy. The use of the composition in TBC systems is not disclosed.

U.S. patent application publication No. 2018/0128952 to Yeh, which discloses a multilayer film structure coated on a surface of a workpiece, in which the multilayer film structure is formed, for example, by stacking at least two layers of a high-entropy material film and at least one layer of a non-high-entropy material film on each otherThe disclosure of the application is incorporated herein by reference in its entirety. The high-entropy material film can be a high-entropy alloy film, a high-entropy nitride film, a high-entropy carbide film, a high-entropy oxynitride film, a high-entropy carbonitride film, a high-entropy oxide film, a high-entropy oxycarbide film and other high-entropy ceramic films. Exemplary high entropy films disclosed are high entropy alloy films with an equiatomic composition of AlCrNbSiTi and a thickness of 0.25 μm, with (AlCrNbSiTi) N, i.e., (Al)₁₀Cr₁₀Nb₁₀Si₁₀Ti₁₀)N₅₀A high-entropy nitride film having a composition of (1) and a thickness of 0.2. mu.m, a high-entropy nitride film having a composition of (CrNbSiTiZr) N and a thickness of 0.15. mu.m, a high-entropy alloy film having a composition of AlCrNbSiTi and a thickness of 0.8. mu.m, a high-entropy alloy film having a composition of (AlCrNbSiTi), a high-entropy alloy film having a thickness of (AlCrNbSiTi)₄₀O₆₀A high-entropy oxide film having a composition of (1) and a thickness of 0.2. mu.m, a high-entropy alloy film having a composition of AlCrNbSiTiZr and a thickness of 0.4. mu.m, a high-entropy alloy film having a composition of (AlCrNbSiTiZr)₅₀C₂₀N₃₀A high entropy carbonitride film having a thickness of 0.4 μm and having a composition of (AlCrNbSiTiZr)₄₀C₂₀N₃₀O₂₀A high-entropy carbooxynitride film having a composition of (e) 0.6 μm and a thickness, a high-entropy nitride film having a composition of (AlCrNbSiTiZr) N and a thickness of 0.2 μm, and a high-entropy carbide film having a composition of (CrNbSiTiZr) C and a thickness of 0.2 μm. The use of the composition in TBC systems is not disclosed.

Metal oxides of the formula MO are disclosed in the following articles, wherein "M" represents five or more oxide forming metals, which are HEOs having the rock salt "NaCl" lattice structure, the disclosures of each of these articles being incorporated herein by reference in their entirety:

1. C. M. Rost, doctor thesis, North Carolina State Univ (2016), "Entropically-stabilized oxides: Explorations of a novel class of multicomponent materials"；

2. C. M. Rost, E. Sachet, T. Borman, A. Moballegh, E. Dickey, D. Hou, J. Jones, S. Curtarolo, J. P. Maria, Nature Communications: 09-25-2015, "Entropy-stabilized oxides"；

3. Moballegh, C. M. Rost, Jon-Paul Maria, E C. Dickey, Microsc. Microanal., 21 (2015), pp. 1349-1350: "Chemical homogeneity in entropy-stabilized complex metal oxides"；

4. Z. Rak, J-P, Maria, D. W. Brenner, Mater Lett: 217 (2018) pp. 300-303: "Evidence for Jahn-Teller compression in the (Mg,Co,Ni,Cu,Zn)O entropy”；

5. C. M. Rost, Z. Rak, D. W. Brenner J.-P. Maria, J. Am Ceramic Society, 100(2017), pp. 2732-2738, " Local structure of the Mg _x Ni _x Co _x Cu _x Zn _x (x=0.2) entropy‐stabilized oxide: An EXAFS study"；

6. Z. Rak, C. M. Rost, M. Lim, P. Sarker, C. Toher, S. Curtarolo, J. P. Maria, D. W. Brenner, J. App. l Phys., 120 (2016) pp. 95-105, "Charge compensation and electrostatic transferability in three entropy-stabilized oxides: results from density functional theory calculations"；

7. G. Anand, A. P. Wynn, C. M. Handley, C. L. Freeman, Acta Mater., 146(2018) pp. 119-125, "Phase stability and distortion in high entropy oxides"；

8. Sarkar, R. Djenadic, N. J. Usharani, K. P. Sanghvi, J. Euro Ceram Soc, 37(2017) pp. 747-754, "Nanocrystalline multicomponent entropy stabilized transition metal oxide"；

9. D. Berardan, S. Franger, D. Dragoe, A. K. Meena and N. Dragoe, Phys. Status Solidi RRL 10, 4(2016), pp. 328-333, "Colossal dielectric constant in high entropy oxides"；

10. D. Berardan, S. Franger, A. K. Meena and N. Dragoe, J. Mater. Chem. A, 24(2016), pp. 9536-9541, “Room temperature Lithium superionic conductivity in high entropy oxides”；

11. D. Berardan, A. K. Meena, S. Franger, C. Herrero and N. Dragoe, J. Alloys and Compounds, 704(2017) pp. 693-700, "Controlled Jahn-Teller distortion in (MgCoNiCuZn)O-based high entropy oxides"；

12. Sarkar, L. Velasco, D. Wang, Q. Wang, G. Talasila, L. de Biasi, C. Kubel, T. Brezesinski, S. Bhattacharya, H. Hahn, B. Breitung, Nature Communications: 08-24-2018, "High entropy oxides for reversible energy storage"；

13. A. Giri, J. Braun, C. M. Rost, P. E Hopkins, Scripta Mater., 138(2017) 134-138, "On the minimum limit to thermal conductivity of multi-atom component crystalline solid solutions based on impurity mass scattering"。

The use of the compositions in TBC systems is not disclosed in these articles.

The formula MO is disclosed in the following articles₂Wherein "M" represents five or more oxide-forming metals, which are fluorite "CaF₂"lattice structured HEO, the disclosure of each of these articles is incorporated herein by reference in its entirety:

14. R. Djenadic, A. Sarkar, O. Clemens, C. Loho, M. Botros, V. Chakravadhanula, C. Kubel, S. Bhattacharya, A. Gandhi, H. Hahn, Mater. Res. Lett. 5(2017), pp. 102-109, "Multicomponent equiatomic rare earth oxides"；

15. K. Chen, X. Pei, L. Tang, H. Cheng, Z. Li, C. Li, X. Zhang, L. An, J. Euro Ceram Soc, 38(2018) pp. 4161-64, "A five-component entropy-stabilized fluorite oxide"；

16. A. Sarkar, C. Loho, L., Velasco, T. Thomas; S. Bhattacharya, H. Hahn, R. Djenadic, Dalton Transactions 36(2017), pp. 12167-176, "Multicomponent equiatomic rare earth oxides"。

the use of the compositions in TBC systems is not disclosed in these articles.

ABO is disclosed in the following article₃Type oxides, wherein a and B are cations, are HEO having a perovskite lattice structure, the disclosure of each of these articles being incorporated herein by reference in their entirety:

17. S. Jiang, T. Hu, J. Gild, N. Zhou, J. Nie, M. Qin, T. Harrington, K. Vecchio, J. Luo, Scripta Mater, 142(2018), pp. 116-120, "A new class of high-entropy perovskite oxides"；

18. A. Sarkar, R. Djenadic, D. Wang, C. Hein, R. Kautenburger, O. Clemens, H. Hahn, J Euro Ceram Soc, 38(2018) pp. 2318-2327, "Rare earth and transition metal based entropy stabilized perovskite type oxides"。

the use of the compositions in TBC systems is not disclosed in these articles.

Formula M is disclosed in the following article₃O₄Wherein "M" represents five or more oxide forming metals, which are HEOs having a spinel lattice structure, the disclosure of each of these articles being incorporated herein by reference in its entirety:

19. J. Dabrowa, M. Stygar, A. Mikula, A. Knapik, K. Mroczka, W. Tejchman, M. Danielewski and M. Martin, Mater. Lett, 216(2018) pp. 32-36, "Synthesis and microstructure of (Co,Cr,Fe,Mn,Ni)₃O₄ high entropy oxide characterized by spinel structure"；

20. A. Navrotsky and O. J. Klepp. a, J. Inorg. Nucl. Chem., vol 29, no. 11, pp. 2701-2714, 1967, “The thermodynamics of cation distributions in simple spinels”。

the use of the compositions in TBC systems is not disclosed in these articles.

Although high entropy oxides are known, their use as topcoat layers in TBCs is not known. For example, the co-inventor Naixie Zhou is a co-author of the 17 th article listed above, which article states: "this study reports for the first time the successful synthesis of high entropy perovskite oxides (i.e., single solid solution phase of multi-cation perovskite oxides with high site shape entropy ≧ 1.5R/mole)".

"High-entry fluorine oxides," Journal of the European Ceramic Society, 38 (2018), 3578-Made with the exception of the four primary cations (Hf) as starting and baseline_0.25Zr_0.25Ce_0.25Y_0.25)O_2-δIn addition to eleven fluorite type oxides with five main cations. Eight of the compositions, i.e., (Hf)_0.25Zr_0.25Ce_0.25Y_0.25)O_2-δ、(Hf_0.25Zr_0.25Ce_0.25)(Y_0.125Yb_0.125)O_2-δ、(Hf_0.2Zr_0.2Ce_0.2)(Y_0.2Yb_0.2)O_2-δ、(Hf_0.25Zr_0.25Ce_0.25)(Y_0.125Ca_0.125)O_2-δ、(Hf_0.25Zr_0.25Ce_0.25)(Y_0.125Gd_0.125)O_2-δ、(Hf_0.2Zr_0.2Ce_0.2)(Y_0.2Gd_0.2)O_2-δ、(Hf_0.25Zr_0.25Ce_0.25)(Yb_0.125Gd _0.125)O_2-δAnd (Hf)_0.2Zr_0.2Ce_0.2)(Yb_0.2 Gd_0.2)O_2-δSingle phase solid solutions with fluorite crystal structure, and high form entropy (on the cation sublattice), similar to those reported in previous studies for high entropy alloys and ceramics. It is disclosed that most high entropy fluorite type oxides (HEFO), in addition to two oxides comprising Yb and Gd at the same time, can be sintered to high relative densities. According to Gild et al with 8 mol% Y₂O₃-stabilized ZrO₂These single phase HEFO exhibit lower conductivity and comparable hardness (even with higher levels of softer components such as Y) compared to (8YSZ)₂O₃And Yb₂O₃As well as so). Notably, these single phase HEFO are disclosed to have thermal conductivities lower than that of 8YSZ, presumably due to high phonon scattering caused by multiple cation and strain lattices. High entropy fluorite type oxide (HEFO) is composed of HfO with equal mole fraction as base material₂、ZrO₂And CeO₂And oxide additives of Y, Yb, Ca, Ti, La, Mg and Gd as fluorite phase stabilizersAnd (4) forming. It is disclosed that the thermal conductivity of YSZ has been extensively studied for its use as a thermal barrier coating at high temperatures. The thermal conductivity was observed to depend on the porosity, manufacturing method and doping level. The measured thermal conductivity of the eight single phase HEFO's is reported to be lower than that of 8 YSZ. However, hafnium is a very heavy metal, and the high hafnium content in these high entropy fluorite type oxides increases the weight and density of the coating, which is less desirable in aerospace applications.

The present invention provides TBC topcoats with lower thermal conductivity, good sintering resistance, excellent phase stability and good thermal cycling performance than currently used TBC topcoats. The topcoat is a high entropy oxide that exhibits a single phase or single crystal structure, such as tetragonal or cubic, over an extended temperature range that can range from room temperature to the topcoat operating temperature of turbine blades of jet engines. The high entropy oxide top coats of the present invention that exhibit a single phase or maintain phase composition without transformation throughout thermal cycling do not delaminate from the thermal bond coat or substrate due to significant volume changes caused by changes in crystal structure or phase changes at high operating temperatures. A high level of hafnium may be included (but is not required), whereby the weight and density of the coating can be reduced while providing low thermal conductivity and maintaining a single phase crystal structure, such as cubic or tetragonal, over an extended period of time and an unexpectedly broad temperature range up to and beyond the operating temperature of the topcoat.

Disclosure of Invention

According to the present invention, a Thermal Barrier Coating (TBC) having low thermal conductivity, which exhibits a single-phase or single-crystal structure, such as tetragonal or cubic, over an extended temperature range, comprises a top-coat layer of a High Entropy Oxide (HEO) having a high azimuthal entropy. In aspects of the invention, the phase composition is substantially preserved with no transition from room temperature to the topcoat operating temperature of the gas turbine component. HEO has M_xO_yWherein M represents at least five different oxide-forming metal cation groups, x represents the number of metal cations (M) or atoms, and y represents the number of oxyanions (O) or atoms. In the present inventionIn certain embodiments, the at least five different oxide-forming metal cations (M) can include: a) at least one, preferably at least two, of the transition metals Sc, Y, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Co, Ni, Cu or Zn, and/or b) at least one, preferably at least two, of the lanthanides La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb or Lu. In some embodiments, the at least one oxide-forming metal cation comprises an alkaline earth metal: be. Mg, Ca, Sr or Ba.

In embodiments of the invention, the thermal barrier coating may comprise at least five different metal oxides, which are:

a) y in an amount of 5 to 18% by weight₂O₃，

b) ZrO in an amount of 12 to 55% by weight₂，

c) CaO in an amount of 0 to 15% by weight,

d) gd in an amount of 0 to 30% by weight₂O₃，

e) La in an amount of 0 to 26% by weight₂O₃，

f) Yb in an amount of 0 to 32% by weight₂O₃，

g) TiO in an amount of 0 to 10 wt%₂Or is or

h) CeO in an amount of 0 to 18% by weight₂，

a) The percentages of the (a) to the (h) amount to at least 97% by weight, preferably between 98% and 100% by weight.

In aspects of the invention, the thermal barrier coating material used to form the topcoat may be in powder form, or in the form of a wire, ingot, rod, or rod. In each case, the chemical composition of the thermal barrier coating material or topcoat material may be as described for the Thermal Barrier Coating (TBC) or topcoat.

In another aspect of the invention, a Thermal Barrier Coating (TBC) system includes a topcoat and a bond coat or bond coating, wherein the topcoat is bonded to the bond coat or bond coating. Coated substrates include a substrate and a thermal barrier coating system bonded to the substrate by a bond coat or coating layer. The thermal barrier coating system may be produced from a thermal spray powder. Thermal barrier coating systems bond to substrates such as superalloys through a bond coat or bond coat layer between the topcoat and the substrate.

In another aspect of the invention, delamination of the topcoat from the substrate is reduced by adhering the topcoat to the substrate with a tie coat or coating layer. The topcoat may include a Thermal Barrier Coating (TBC), and the substrate may include a gas turbine engine component.

Drawings

The invention is further illustrated by the accompanying drawings, in which:

FIG. 1 schematically illustrates a coated substrate having a Thermal Barrier Coating (TBC) system comprising a topcoat, such as a Thermal Barrier Coating (TBC), bonded to a bond coat or coating layer in accordance with the present invention.

Fig. 2 shows the morphology (SEM micrograph) of the HEO agglomerated and sintered powder of sample HEO 1.

Fig. 3 shows a cross section (SEM micrograph) of the HEO agglomerated and sintered powder of sample HEO 1.

Fig. 4 shows a cross-sectional microstructure (SEM micrograph) of a HEO thermal barrier coating, TBC topcoat, of sample HEO 1.

Fig. 5 shows the morphology (SEM micrograph) of the HEO agglomerated and sintered powder of sample HEO 2.

Fig. 6 shows a cross section (SEM micrograph) of the HEO agglomerated and sintered powder of sample HEO 2.

Fig. 7 shows the cross-sectional microstructure (SEM micrograph) of the HEO thermal barrier coating, TBC topcoat, of sample HEO 2.

Fig. 8 shows the morphology (SEM micrograph) of the HEO agglomerated and sintered powder of sample HEO 3.

Fig. 9 shows a cross section (SEM micrograph) of the HEO agglomerated and sintered powder of sample HEO 3.

Fig. 10 shows the cross-sectional microstructure (SEM micrograph) of a thermal barrier coating, TBC topcoat, agglomerated and sintered by HEO of sample HEO 3.

Fig. 11 shows the morphology (SEM micrograph) of the HEO agglomerated and sintered powder of sample HEO 4.

Fig. 12 shows a cross section (SEM micrograph) of the HEO agglomerated and sintered powder of sample HEO 4.

Fig. 13 shows the cross-sectional microstructure (SEM micrograph) of a thermal barrier coating, TBC topcoat, agglomerated and sintered by HEO of sample HEO 4.

Fig. 14 shows an experimental XRD spectrum of sample HEO 4.

Detailed Description

A topcoat, such as a Thermal Barrier Coating (TBC), for a thermal barrier coating system including a topcoat and at least one bond coat for bonding with a substrate, such as a superalloy for use in high temperature gas turbine engine components. There may also be a plurality of top coats on top of the at least one tie coat. The invention also provides a thermal barrier coating material or a top coating material for making a top coating or a thermal barrier coating. TBC topcoats exhibit low thermal conductivity, good sintering resistance, excellent phase stability, and good thermal cycling performance. The topcoat is a high entropy oxide that exhibits a single phase or single crystal structure, such as tetragonal or cubic, over a long period of time in an unexpectedly wide temperature range that can range from room temperature to the operating temperature of the topcoat for turbine blades in jet engines. The high entropy oxide top coat of the present invention, which appears as a single phase throughout the thermal cycle, does not delaminate from the thermal bond coat or substrate at high operating temperatures due to significant volume changes caused by crystal structure changes or phase changes as well as thermal internal stresses. Low coating weight and low coating density are achieved while providing low thermal conductivity and maintaining a single phase crystal structure such as cubic or tetragonal over extended periods of time and an unexpectedly broad temperature range up to and beyond the topcoat service temperature (which may be at least 1800 °, e.g., 2,000 ° f or higher, preferably at least 2300 ° f, or up to the melting point of the TBC topcoat). In embodiments of the invention, more than one phase or crystal structure may be present in the top coat or thermal barrier coating, provided that it does not disadvantageously result in a significant volume change caused by the crystal structure change, thereby causing delamination. Although it is most preferred that there is only a single phase or crystal structure, i.e. 100% phase volume (as measured, for example, by X-ray diffraction), in embodiments of the invention where two or more phases or crystal structures are present, the predominant phase volume fraction may be, for example, at least 80%, preferably at least 90%, more preferably at least 98%.

TBC coatings bonded to substrates such as superalloys using bond coats exhibit unexpectedly high resistance to thermal cycle fatigue.

TBC topcoats and TBC materials used to make the topcoats are High Entropy Oxides (HEOs) with high azimuthal entropy. In aspects of the invention, a single phase may be maintained without transitioning from room temperature to the operating temperature of the topcoat of the turbine component to another phase or crystalline structure. HEO in the form of M_xO_yWherein M represents at least five different oxide-forming metal cation groups, x represents the number of metal cations (M) or atoms, and y represents the number of oxygen anions (O) or atoms.

In embodiments of the invention, the TBC topcoat and TBC materials used to make the topcoat, and the HEO, are single phase or single crystal structures for an unexpectedly wide temperature range, such as for a temperature range of at least 700 ° f, preferably at least 1,000 ° f, most preferably at least 1,500 ° f (below or up to the topcoat maximum service temperature or melting point of the HEO), where the HEO does not undergo a phase transition to a different crystal structure. For example, in aspects of the present invention, if the maximum operating temperature in a turbine engine component is 2,000 ° f, from 1300 ° f to 2,000 ° f, preferably from 1,000 ° f to 2,000 ° f, most preferably from 500 ° f to 2,000 ° f, or more preferably from room temperature to 2000 ° f or higher, preferably to at least 2300 ° f, such as to the melting point 2400 ° f of the HEO, which may have a single phase or single crystal structure. In aspects of the invention, the HEO may be a single phase or single crystal structure throughout the entire temperature range of 800 ° f, extending from 1800 ° f to 2600 ° f or from 1300 ° f to 2100 ° f. The wider the temperature range without phase change, the better, because the number of phase changes will be less, for example, as the topcoat is cycled above and below the turbine operating temperature or as the operating temperature fluctuates, thus helping to reduce thermal expansion and contraction and thermal stresses.

In various preferred aspects of the invention, the TBC topcoat, TBC coating material, and HEO may have only a single phase or single crystal structure, e.g., only cubic or tetragonal, from room temperature to at least 1800 f, preferably to at least 2,000 f, more preferably to at least 2300 f, e.g., from room temperature to the melting point of the HEO. In embodiments of the invention, the HEO has a melting point of at least 1,150 ℃ (2,102 ° f), preferably at least 1,300 ℃ (2,372 ° f), and more preferably at least 1,315 ℃ (2,399 ° f).

In embodiments of the invention, the HEO topcoat or coating layer may have an intrinsic thermal conductivity of less than 1.5 (W/m-K), preferably less than 1.2 (W/m-K), and more preferably less than 0.9W/m-K at 25 ℃. In embodiments of the invention, the density of the HEO coating may be lower than theoretical (i.e., may include porosity), thus reducing the thermal conductivity of the HEO topcoat to less than 1.3 (W/m-K), preferably less than 1.0 (W/m-K), and more preferably less than 0.8 (W/m-K). Table 2 shows this.

In embodiments of the invention, the Archimedes density of the TBC topcoat or coating layer may be less than 7g/cm³E.g. from 5 g/cm³To 6.5 g/cm³Preferably less than 6.3 g/cm³E.g. from 5.25 g/cm³To 6.25 g/cm³More preferably less than 6.0 g/cm³E.g. from 5.30 g/cm³To 5.90 g/cm³。

In embodiments of the invention, an oxide ceramic or HEO intended for use as a thermal insulation material or thermal barrier coating may have an overall combined atomic composition, which may be represented as M_xO_yWherein M represents at least five different groups of oxide-forming metal cations and wherein the formal entropy of the oxides, S_{Bit shape}Is 1.5R/mole or greater, wherein R is a gas constant of 8.314 J.K^{- 1}.mol^-1(ii) a Using S_{Bit shape}This definition of value is a generally accepted definition of high entropy material. The metal cation "M" and the oxyanion "O" may be distributed on one or more crystal sublattices. In aspects of the invention, the TBC topcoat may have a metamorphosis entropy of oxide S of less than 1.5R/mole, such as 1.0R/mole or greater, or 1.3R/mole or greater_{Bit shape}Provided that the thermal conductivity is low and that the metal oxide retains the phase composition over an unexpectedly wide temperature range as described above, wherein the metal oxide does not undergo a phase transition and the major phase volume fraction is maintained, for example, at least 80%, preferably at least 90%, more preferably at least 98% and the melting point is above the coating operating temperature as described above.

M_xO_yIs a standard metallurgical abbreviation. For example, carbide (Cr, Mo, W, Fe)₂₃C₆Commonly referred to as M₂₃C₆. In the same way, M_xO_yCan be used for describing oxide (Zr, Ce, Y, Yb, Gd, Dy)_xO_yWherein "M" represents five or more oxide-forming metals.

In embodiments of the invention, these metals "M" may preferably be selected from the group of non-toxic and non-radioactive oxide forming metals, such as:

transition metal:

• Sc、Y

• Ti、Zr、Hf

• V、Nb、Ta

• Cr、Mo、W

• Mn、Re

fe, Ru, Co, Ni, Cu, Zn, and

lanthanide series elements:

La、Ce、Pr、Nd、Pm、Sm、Eu、Gd、Tb、Dy、Ho、Er、Yb、Lu。

in some embodiments of the invention, the at least one alkaline earth metal may preferably be selected from, for example

• Be、Mg、Ca、Sr、Ba。

In an embodiment of the present invention, the following metals are more preferably used in the HEO TBC:

transition metal:

• Y

• Ti、Zr、Hf、V

• Cr、Mo、W

lanthanide series elements:

• La、Ce、Pm、Sm

• Eu、Gd

• Tb

• Dy、Er、Yb。

in some embodiments of the invention, the at least one alkaline earth metal is more preferably selected from such as

•Mg、Ca。

In an embodiment of the present invention, at least one, preferably at least two, transition metals and/or at least one, preferably at least two, lanthanides may be used in the at least five different oxide forming metal cations (M).

Although hafnium (Hf) has a very high melting point, in embodiments of the invention, hafnium may be eliminated or used in low amounts, e.g., less than 2.0 wt%, preferably less than 1 wt%. Although higher amounts of hafnium may be used, for example up to 15% by weight or more, high levels of hafnium are not necessary so that the coating weight and density can be reduced while providing low thermal conductivity and maintaining a single phase crystal structure such as cubic or tetragonal for long periods of time over an unexpectedly wide temperature range up to and beyond the operating temperature of the topcoat.

In addition, the metal cation "M" and the oxyanion "O" may be distributed on one or more crystal sublattices. This means oxides such as the exemplary oxides (Zr, Ce, Y, Yb, Gd, Dy)_xO_yPossibly physically represented by a composite oxide structure (Zr, Ce, Y, Yb, Gd, Dy) of hitherto unknown crystallography_xO_yOr may divide itself into 2 (or more) more well-known lattices such as (Y, Yb, Gd, Dy)₂O₃And (Zr, Ce) O₂. Thus, in the latter case, this would mean that there are 2 atoms from the (Y, Yb, Gd, Dy) group for every 3 oxygen atoms and 1 atom from the (Zr, Ce) group for every 2 oxygen atoms in the overall composition. When these oxide lattices are intimately mixed, it is not necessarily possible to detect the individual phases in the HEO structure when examined by scanning electron microscopy.

In various aspects of the invention, known high entropy oxides (such as those in the references discussed and listed above, which are incorporated herein by reference in their entirety) can be used as top coats, provided they are predominantly of single phase or single crystal structure such as tetragonal or cubic type, provided that the thermal conductivity is low and the metal oxide retains the phase composition over an unexpectedly wide temperature range as described above, and the melting point is higher than the coating operating temperature as described above. Most preferably, the HEO should not undergo a significant transition nor change the phase fraction from room temperature to the topcoat service temperature or melting point as described above.

In embodiments according to the invention, the thermal barrier coating may comprise a top coat, wherein the top coat is a High Entropy Oxide (HEO) with high azimuthal entropy, said HEO being M_xO_yForm wherein M represents a group of at least five different oxide forming metal cations, x represents a number of metal cations (M) or atoms, and y represents a number of oxygen anions (O) or atoms, HEO is monophasic throughout the working temperature range of the topcoat, and the at least five different oxide forming metal cations (M) may include:

a) at least one of an alkaline earth metal, i.e. Be, Mg, Ca, Sr or Ba, of group II of the periodic Table of the elements, and/or

b) At least one transition metal selected from Sc, Y, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Co, Ni, Cu or Zn, and/or

c) At least one of lanthanide La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb or Lu.

In preferred embodiments of the thermal barrier coating, the at least five different oxide-forming metal cations (M) may include:

a) at least one of transition metals Y, Ti, Zr, V, Cr, Mo or W, and/or

b) At least one of the lanthanides La, Ce, Pm, Sm, Eu, Gd, Tb, Dy, Er or Yb, and

c) in some embodiments, the ratio of alkaline earth metal: at least one of Mg or Ca.

More preferably, the at least five different oxide forming metal cations (M) of the thermal barrier coating comprise at least five of Y, Zr, Ca, Gd, La, Yb, Ti or Ce.

In aspects of the invention, the thermal barrier coating and the thermal barrier coating material or topcoat material may include at least five different metal oxides that are:

a) in an amount of 5 to 20% by weight, preferably 8 to 18% by weight of Y₂O₃，

b) ZrO in an amount of 12 to 55% by weight, preferably 17 to 52% by weight₂，

c) CaO in an amount of 0 to 15% by weight, preferably 0 to 11% by weight,

d) gd in an amount of 0 to 30% by weight, preferably 0 to 28% by weight₂O₃，

e) La in an amount of 0 to 26% by weight, preferably 0 to 24% by weight₂O₃，

f) Yb in an amount of 0 to 32% by weight, preferably 0 to 30% by weight₂O₃，

g) TiO in an amount of 0 to 10 wt.%, preferably 0 to 7 wt%₂Or is or

h) CeO in an amount of 0 to 18% by weight, preferably 0 to 15% by weight₂，

a) The percentages by way of h) add up to 100% by weight. In embodiments, the thermal barrier coating and the thermal barrier coating material or topcoat material may further comprise at least one additional metal oxide, such as HfO₂、SiO₂MgO or Al₂O₃As melting point regulators, stabilizers, dopants or impurities, amounts of up to 3% by weight, for example up to 2% by weight or less than or equal to 1% by weight, the percentages by weight of all oxides totaling up to 100% by weight. In embodiments of the invention, the percentages of the five metal oxides may total up to at least 97% by weight, for example at least 99% by weight, and the additional metal oxide(s) may be present in an amount up to 3% by weight or up to 1% by weight.

In a more preferred embodiment, the thermal barrier coating and the thermal barrier coating material or topcoat material may comprise at least five different metal oxides including: it is composed ofY in an amount of 8 to 12% by weight₂O₃ZrO in an amount of 48 to 55% by weight₂In an amount of 14 to 18% by weight of Yb₂O₃In an amount of 4 to 8% by weight of TiO₂And CeO in an amount of 12 to 17% by weight₂The stated percentages amounting to 100% by weight. Hafnium and further other metal oxides may optionally be included in an amount up to 2% by weight, e.g. less than or equal to 1% by weight, the weight percentages of all oxides totaling up to 100% by weight.

In other preferred embodiments, the thermal barrier coating and the thermal barrier coating material or topcoat material may comprise at least five different metal oxides including:

three metal oxides of which are

Y in an amount of 13 to 19% by weight₂O₃，

ZrO in an amount of 14 to 25% by weight₂，

In an amount of 20 to 30% by weight of Gd₂O₃And are and

any two of the following metal oxides:

yb in an amount of 23 to 32% by weight₂O₃，

La in an amount of 18 to 25% by weight₂O₃Or is or

CaO in an amount of 6 to 12% by weight,

the percentages of the five metal oxides add up to at least 97% by weight, preferably from 98% to 100% by weight.

In embodiments of the invention, the TBC coating material or HEO may be manufactured in powder form or in bulk form such as wire, rod or ingot form. The TBC coating material powder may be a homogeneous mixture of individual powders of each component of the TBC coating material. The TBC coating material powder may also be comprised of particles that each contain all or some of the components of the bond coat material. For example, a bulk form of the TBC topcoat material or all components of the HEO may be ground to obtain a powder. The particle size of the TBC coating material may depend on the coating method employed. Conventional particle size distributions conventionally employed for a given coating process can be used for the TBC topcoat material or HEO of the present invention.

The bond coat material may be any conventional or known bond coat material, such as those used for coatings for gas turbine engine parts, such as the known MCrAlY bond coat used to bond TBC topcoats to substrates such as superalloys. For example, M may represent Ni, Co, Fe, or a combination thereof. To improve the performance of the bond coat, Hf, Re and Pt and various other rare earth elements can often be added to the advanced bond coat. Non-limiting examples of bond coat materials that may be used include those disclosed in U.S. patent No. 4,117,179 to Jackson et al, U.S. patent No. 5,141,821 to lugcheider, and U.S. patent No. 4,275,124 to McComas et al, the disclosures of each of which are incorporated herein by reference in their entirety.

The substrate may be any known or conventional material or article requiring a topcoat or barrier coating (TBC). Non-limiting examples of substrates include alloys or superalloys used to make gas turbine engine parts, such as Hastelloy @, disclosed in U.S. Pat. No. 4,124,737 to Wolfa et al, the disclosure of which is incorporated herein by reference in its entirety. Hastelloy as disclosed in Wolfa et al has the following nominal composition: 22.0% by weight of chromium; 9.0 wt% molybdenum; 8.5 wt.% iron; 1.5 wt% cobalt; 0.6 wt% tungsten; 1.0 wt.% silicon; 1.0 wt.% manganese; 0.1 wt% carbon; and the balance nickel. Other non-limiting examples of known and conventional substrates that may be coated with the TBC topcoat of the present invention include steel, stainless steel, other iron-based alloys with low alloying content, chromium and chromium-based alloys, and refractory metals and refractory metal-based alloys. Non-limiting examples of superalloy substrates that may be coated with the TBC coatings of the present invention are known carbide-reinforced superalloys, such as nickel-based and cobalt-based superalloys, directionally solidified nickel-based and cobalt-based superalloys, including eutectic alloys, and refractory alloys as disclosed in U.S. Pat. No. 4,117,179, the disclosure of which is incorporated herein by reference in its entirety. Non-limiting examples of substrates or articles that can be coated with the TBC topcoat of the present invention include components used in the hot areas of gas turbines and various jet engine components.

In another aspect of the invention, as schematically illustrated in fig. 1, a Thermal Barrier Coating (TBC) system 1 includes a topcoat 2 and a bond coat or bond coat layer 3, wherein the topcoat 2, such as the TBC, is bonded to the bond coat or bond coat layer 3 at a topcoat/bond coat interface 5. The coated substrate 10 includes a substrate 15 and a thermal barrier coating system 1 bonded to the substrate 15 at a substrate/bond coat interface 20 by a bond coat or coating layer 3. The thermal barrier coating system 1 may be produced from a thermal spray powder. The thermal barrier coating system 1 is bonded to a substrate 15, such as a superalloy or a gas engine turbine component, by a bond coat or bond coat layer 3 between the topcoat 2 and the substrate 15.

In embodiments of the invention, multiple bond coats or bond coat layers 3 and multiple topcoat layers 2 may be employed, wherein each topcoat layer 2 is placed on top of the bond coat layer 3 in an alternating manner to provide multiple TBC systems 1, stacked and bonded to each other, with the lowermost bond coat layer 3 bonded to the substrate 15.

In another aspect of the invention, a method is provided for reducing delamination of a TBC topcoat from a substrate by bonding the TBC topcoat with a single phase or single crystal structure (such as a tetragonal or cubic crystal structure) to the substrate with a bond coat or coating layer.

TBC top coats or HEOs and bond or bond coats or bond layers can be deposited, applied or laminated on the substrate using conventional thermal spray processes such as air plasma spray, suspension plasma, high velocity oxy-fuel spray (HVOF), Low Pressure Plasma Spray (LPPS), Vacuum Plasma Spray (VPS), Chemical Vapor Deposition (CVD), plasma physical vapor deposition (PS-PVD), Physical Vapor Deposition (PVD) including vacuum deposition methods such as sputtering and evaporation, and conventional flame spray processes such as combustion wire spray and combustion powder spray, electric arc wire spray, powder flame spray, and Electron Beam Physical Vapor Deposition (EBPVD). The bond coat or coating layer and top coat or TBC or HEO may be applied at conventional and known coating thicknesses.

In embodiments of the present invention, a thermal barrier coating material or a HEO material may be manufactured by agglomerating and sintering a thermal barrier coating material to obtain sintered agglomerates, and forming the sintered agglomerates into a powder for thermal spraying using known techniques and processes. Agglomeration and sintering is a particularly novel way of making HEO. This process is advantageous because: 1) diffusion pathways are reduced, and 2) are more suitable for industrial production. Reducing the diffusion path is highly advantageous because homogenizing high temperature materials into a single phase can be both expensive and time consuming when compared to other processes. In embodiments of the present invention, a thermal barrier coating may be manufactured by agglomerating and sintering a thermal barrier coating material to obtain sintered agglomerates, and forming the sintered agglomerates into a powder for thermal spraying using known process parameters and techniques.

The invention is further illustrated by the following non-limiting examples in which all parts, percentages, ratios and ratios are by weight, all temperatures are in degrees Celsius and all pressures are atmospheric, unless otherwise specified.

Examples

The compositions (as powders) of four inventive HEO TBC coating materials used to make inventive HEO TBC coatings for coated substrates are shown in table 1.

The compositions of the samples tested and the test results are given in table 1 below:

table 1: composition of HEO TBC topcoat coating material for making HEO TBC topcoat for coated substrates

For TBC topcoat material (HEO): the coating density, relative density, coating phase and thermal conductivity measured at 25 ℃ are shown in table 2.

Table 2 results of the properties of the samples tested are as follows:

table 2: properties of HEO TBC topcoat

Properties of	Measurement Unit	HEO 1	HEO 2	HEO 3	HEO 4
						Archimedes density	g/cm3	5.36	5.72	6.23	5.87
Relative density	%	91.8	92.3	92.7	93.1
						Major phase fraction (% by volume) from XRD	Volume%	65%	87%	>98%	>99%
Thermal conductivity at 25 DEG C	W/m-K	1.22	1.30	1.21	0.77

Powder morphology (SEM micrographs), powder cross-section (SEM micrograph), and coating microstructure (SEM micrograph) of the HEO agglomerated and sintered thermal barrier coating of samples HEO 1, HEO 2, HEO 3, and HEO 4 are shown in fig. 2-13. An example of the X-ray diffraction pattern of HEO 4, one of the HEO complexes, is shown in fig. 14.

Moreover, at least because the invention is disclosed herein in a manner that enables one to make and use the invention, for example, such as by way of illustration of specific exemplary embodiments for simplicity or efficiency, the invention may be practiced without any of the steps, other elements, or other structure not specifically disclosed herein.

It should be noted that the foregoing embodiments have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the present invention has been described with reference to exemplary embodiments, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein; rather, the invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.